Zygote (Cambridge, England)最新文献

{"title":"Effect of androstenedione on the growth and meiotic competence of bovine oocytes from early antral follicles.","authors":"Hiroaki Taketsuru,&nbsp;Yuji Hirao,&nbsp;Naoki Takenouchi,&nbsp;Kosuke Iga,&nbsp;Takashi Miyano","doi":"10.1017/S0967199411000268","DOIUrl":"https://doi.org/10.1017/S0967199411000268","url":null,"abstract":"<p><p>Medium that contains 17β-estradiol has been reported to support in vitro growth of bovine oocytes, isolated from early antral follicles, until the final stage. The aim of this study was to determine the effects of androstenedione in medium on such growing bovine oocytes. Oocyte-granulosa cell complexes were collected from early antral follicles and cultured for 14 days in medium supplemented with 17β-estradiol (0, 10 and 100 ng/ml) or androstenedione (0, 10 and 100 ng/ml). The mean diameter of oocytes measured after seeding on the culture substrate was 96.9 μm (n = 191). Either steroid was necessary for maintainance of the organization of oocyte-granulosa cell complexes over the 14-day culture period. In the 17β-estradiol- or the androstenedione-supplemented medium about 80% or 65%, respectively, of viable oocytes were recovered. In both groups the increase in oocyte size was significant after 14 days. The in vitro grown oocytes were cultured for a further 22-24 h for oocyte maturation; 13% and 30% of oocytes grown in the 10 and 100 ng/ml 17β-estradiol-supplemented medium reached metaphase II, respectively; more than 64% of oocytes grown in the androstenedione-supplemented medium matured to metaphase II. These results show that androstenedione, as 17β-estradiol, can maintain the viability of bovine oocyte-granulosa cell complexes and support the growth of oocytes, and that androstenedione promotes the acquisition of oocyte meiotic competence efficiently at a low dose.</p>","PeriodicalId":136608,"journal":{"name":"Zygote (Cambridge, England)","volume":" ","pages":"407-15"},"PeriodicalIF":1.7,"publicationDate":"2012-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S0967199411000268","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40140501","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of cations as components of jelly coats in Bufo arenarum fertilization.","authors":"Marcela Fátima Medina,&nbsp;Claudia Alejandra Crespo,&nbsp;Inés Ramos,&nbsp;Silvia Nélida Fernández","doi":"10.1017/S0967199409990037","DOIUrl":"https://doi.org/10.1017/S0967199409990037","url":null,"abstract":"<p><p>The role of monovalent (Na+, K+) and divalent (Ca2+, Mg2+) cations in Bufo arenarum fertilization was analysed. Our results showed that the highest fertilization percentages were obtained when strings of uterine oocytes (UO) were inseminated. Under these conditions, full jelly (FJ), which represents the jelly coats surrounding the oocytes at the time of deposition, contained 68.5 +/- 7.0 mM Na+, 27.4 +/- 2.4 mM K+, 6.3 +/- 0.9 mM Ca2+ and 6.9 +/- 0.9 mM Mg2+. When the strings of oocytes were washed in deionized water, these cations diffused into the liquid medium surrounding them. There was a marked similarity between the loss of Ca2+ in the jelly and the decrease in the fertilizability of the UO. Furthermore, the use of chelating agents of divalent cations showed the importance of the Ca2+ contained in the jelly. When Ca2+ was sequestered from the jelly coats by the addition of the chelating agents to the insemination medium as well as by pretreatment of the UO strings, a decrease in fertilization percentages occurred, this effect being dose dependent and more marked with EGTA. These results demonstrate that the Ca2+ in the jelly plays a role in fertilization. Nevertheless, taking into account that during the washing of the jelly other jelly coat components were diffused and considering that the addition of Ca2+ to the insemination medium reverted significantly, but only partially, the loss of fertilizability of jellied UO (washed), the participation of other components in the fertilization mechanism is suggested.</p>","PeriodicalId":136608,"journal":{"name":"Zygote (Cambridge, England)","volume":" ","pages":"69-80"},"PeriodicalIF":1.7,"publicationDate":"2010-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S0967199409990037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40020362","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Involvement of the dehydroleucodine alpha-methylene-gamma-lactone function in GVBD inhibition in Bufo arenarum oocytes.","authors":"G Sánchez Toranzo,&nbsp;L A López,&nbsp;J Zapata Martínez,&nbsp;M C Gramajo Bühler,&nbsp;M I Bühler","doi":"10.1017/S0967199409990086","DOIUrl":"https://doi.org/10.1017/S0967199409990086","url":null,"abstract":"<p><p>Dehydroleucodine (DhL), a sesquiterpenic lactone, was isolated and purified from aerial parts of Artemisia douglasiana Besser, a medicinal herb used in Argentina. DhL is an alpha-methylene butyro-gamma-lactone ring connected to a seven-membered ring fused to an exocyclic alpha,beta-unsaturated cyclopentenone ring. It has been previously shown that DhL selectively induces a dose-dependent transient arrest in G2 of both meristematic cells and vascular smooth muscle cells. Treatment with DhL induces an inhibition of spontaneous and progesterone-induced maturation in a dose-dependent manner in Bufo arenarum fully grown oocytes arrested at G2, at the beginning of meiosis I. However, the nature of the mechanisms involved in the process is still unknown. The aim of this work was to analyse whether DhL's alpha-methylene-gamma-lactone function is responsible for the inhibition effect on meiosis reinitiation of Bufo arenarum oocytes as well as some of the transduction pathways that could be involved in this effect using a derivative of DhL inactivated for alpha-methylenelactone, the 11,13-dihydro-dehydroleucodine (2H-DhL). The use of 2H-DhL in the maturation promoting factor (MPF) amplification experiments by injection of both cytoplasm with active MPF and of germinal vesicle content showed results similar to the ones obtained with DhL, suggesting that the hydrogenated derivative would act in a similar way to DhL. Pretreatment with DhL or 2H-DhL did not affect the percentage of germinal vesicle breakdown (GVBD) induced by H89, a protein kinase A (PKA) inhibitor, which suggests that these lactones would act on another step of the signalling pathway that induces MPF activation. The fact that both DhL and 2H-Dhl inhibit GVBD induced by okadaic acid microinjection suggests that they could act on the activity of the Myt1 kinase. This idea is supported by the experiments of injection of GV contents in which an inhibitory effect of these lactones on GVBD was also observed. Our results indicate that the inhibitory effect on meiosis progression of DhL does not depend only on the activity of the alpha-methylenelactone function, as its hydrogenated derivative, 2H-DhL, in which this function has been inactivated, causes similar effects on amphibian oocytes. However, 2H-DhL was less active than DhL as higher doses were required to obtain a significant inhibition. On the other hand, the analysis of the participation of certain mediators in some of the signalling pathways leading to MPF activation suggests that the Myt1 kinase could be a target of these lactones, while cdc25 phosphatase would not be affected. Besides, the PKA inhibition assays indicate that these lactones would act earlier in the signalling pathways.</p>","PeriodicalId":136608,"journal":{"name":"Zygote (Cambridge, England)","volume":" ","pages":"41-9"},"PeriodicalIF":1.7,"publicationDate":"2010-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S0967199409990086","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40020363","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"5-AZA-2'-deoxycytidine (5-AZA-CdR) leads to down-regulation of Dnmt1o and gene expression in preimplantation mouse embryos.","authors":"Jian-Ning Yu,&nbsp;Chun-Yang Xue,&nbsp;Xu-Guang Wang,&nbsp;Fei Lin,&nbsp;Chun-Yi Liu,&nbsp;Fu-Zeng Lu,&nbsp;Hong-Lin Liu","doi":"10.1017/S0967199408005169","DOIUrl":"https://doi.org/10.1017/S0967199408005169","url":null,"abstract":"<p><p>5-AZA-2'-deoxycytidine (5-AZA-CdR) is a demethylating, teratogenic agent and a mutagen, which causes defects in the developing mouse and rat after implantation. Our previous data indicated that 5-AZA-CdR (0.2 and 1.0 muM) inhibited the development of mouse preimplantation embryos. Pronuclear embryos exposed to 5-AZA-CdR at the pronuclear stage were unable to form 8-cell embryos, while 2-cell-stage embryos exposed to 5-AZA-CdR only developed into uncompacted 8-cell-stage embryos. And there was no formation of blastocysts when 4-cell embryos cultured in 5-AZA-CdR. In our present study, we detected Dnmt1o protein and some developmental gene expression in order to find the reasons for the developmental arrest. Dnmt1o could not traffic to 8-cell nuclei as control when embryos were exposed to 5-AZA-CdR. Dnmt1o was in cytoplasm at 2-cell and 4-cell stages before and after treated with 5-AZA-CdR. Gene expression changes were also detected in this research. Our data indicated that connexin 31 (Cx31), connexin 43 (Cx43), connexin 45 (Cx45), E-cadherin (Cdh1) and beta-catenin (Ctnnb1) were all downregulated by 5-AZA-CdR. Cx31, Cx43 and Cx45 are members of connexins family, which have a central role in gap junctions. Cdh1 and Ctnnb1 are necessary for the foundation of tight junctions. Therefore, developmental arrest induced by 5-AZA-CdR may be caused by the failure of Dnmt1o cytoplasmic-nuclear traffic and the down-regulation of developmental gene expression. Normal compaction and blastocoel cavitation need Dnmt1o traffic to 8-cell nuclei and the right gene expression, especially the correlative genes in gap junctions and tight junctions.</p>","PeriodicalId":136608,"journal":{"name":"Zygote (Cambridge, England)","volume":" ","pages":"137-45"},"PeriodicalIF":1.7,"publicationDate":"2009-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S0967199408005169","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39968979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Expression of voltage-activated calcium channels in the early zebrafish embryo.","authors":"Dayán Sanhueza,&nbsp;Andro Montoya,&nbsp;Jimena Sierralta,&nbsp;Manuel Kukuljan","doi":"10.1017/S0967199408005108","DOIUrl":"https://doi.org/10.1017/S0967199408005108","url":null,"abstract":"<p><p>Increases in cytosolic calcium concentrations regulate many cellular processes, including aspects of early development. Calcium release from intracellular stores and calcium entry through non-voltage-gated channels account for signalling in non-excitable cells, whereas voltage-gated calcium channels (CaV) are important in excitable cells. We report the expression of multiple transcripts of CaV, identified by its homology to other species, in the early embryo of the zebrafish, Danio rerio, at stages prior to the differentiation of excitable cells. CaV mRNAs and proteins were detected as early as the 2-cell stages, which indicate that they arise from both maternal and zygotic transcription. Exposure of embryos to pharmacological blockers of CaV does not perturb early development significantly, although late effects are appreciable. These results suggest that CaV may have a role in calcium homeostasis and control of cellular process during early embryonic development.</p>","PeriodicalId":136608,"journal":{"name":"Zygote (Cambridge, England)","volume":" ","pages":"131-5"},"PeriodicalIF":1.7,"publicationDate":"2009-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S0967199408005108","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39968720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The oocyte activation and Ca2+ oscillation-inducing abilities of mouse and human dead (sonicated) spermatozoa.","authors":"Hiroyuki Yazawa,&nbsp;Kaoru Yanagida,&nbsp;Shoutaro Hayashi,&nbsp;Akira Sato","doi":"10.1017/S0967199408005157","DOIUrl":"https://doi.org/10.1017/S0967199408005157","url":null,"abstract":"<p><p>In ICSI procedures, it is well known that the selection of viable (live) spermatozoa and certain types of immobilization prior to injection is very important for obtaining successful results, but unfortunately there are rare situations when only immotile spermatozoa are available (such as in severe asthenozoospermia or necrozoospermia). In such cases, failure of oocyte activation after ICSI often occurs and may be due to the lack of SOAF (sperm-borne oocyte activating factor) activity. In order to investigate the SOAF activities of dead spermatozoa, mouse and human spermatozoa were immobilized (killed by sonication), maintained in THF medium for varying time intervals (up to 72 h) and then injected into mature unfertilized mouse oocytes. Injected mouse oocytes were examined for their activation, development into blastocysts and Ca2+ responses by imaging and confocal laser scanning microscope. The rates of oocyte activation, blastocyst development and normal patterns of Ca2+ oscillation from the killed-sperm-injected oocytes decreased gradually in accordance with the maintenance interval between sonication and injection. For injection with mouse sonicated spermatozoa, the rate of normal Ca2+ oscillations declined first (after a 3 h maintenance interval) and then blastocyst development was gradually obstructed (after approx. 10 h). The oocyte activation-inducing ability of dead spermatozoa was maintained for a relatively long period, but began to decline after 20 h. The activation rates and Ca2+ response of the oocytes that were injected with human sonicated spermatozoa decreased earlier than those injected with mouse spermatozoa. Although the oocyte activation-inducing ability was maintained for a relatively long time after the death of the spermatozoa, embryo development into blastocysts and the rate of normal Ca2+ oscillations declined after a short maintenance interval between sonication and injection. The Ca2+ response seemed to be the most sensitive indicator for the evaluating the SOAF activity of dead (killed) spermatozoa.</p>","PeriodicalId":136608,"journal":{"name":"Zygote (Cambridge, England)","volume":" ","pages":"175-84"},"PeriodicalIF":1.7,"publicationDate":"2009-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S0967199408005157","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"39968603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Secretion of stem cell factor and granulocyte-macrophage colony-stimulating factor by mouse embryos in culture: influence of group culture.","authors":"A P Contramaestre,&nbsp;F Sifontes,&nbsp;R Marín,&nbsp;M I Camejo","doi":"10.1017/S0967199408004760","DOIUrl":"https://doi.org/10.1017/S0967199408004760","url":null,"abstract":"<p><p>Previous studies showed that the addition of a growth factor to the culture medium could modulate embryo development. The possible secretion of different factors to the culture medium by the embryo itself, however, has been poorly evaluated. The present study was designed to investigate: (1) the influence of single or group culture on the development of 2-cell mouse embryos (strain CD-1) to the blastocyst stage; (2) the release of granulocyte-macrophage colony-stimulating factor (GM-CSF) and stem cell factor (SCF) into the culture medium by the embryo; and (3) the levels of GM-CSF and SCF in the culture medium from both single and group embryos. Two-cell CD-1 mouse embryos were cultured for 96 h singly or in groups of five embryos per drop. GM-CSF and SCF were assayed by ELISA in the complete culture medium. It was found that embryos cultured in groups gave a higher percentage of total blastocyst formation and hatched blastocyst when compared with single embryo culture. The mouse embryos secreted GM-CSF and SCF to the culture medium. The concentration of these cytokines is significantly higher in the group cultures than the level found in single cultures. In conclusion, mouse embryos in culture secrete GM-CSF and SCF to the culture medium and the concentration of these cytokines increases during communal culture. These factors may be operating in both autocrine and paracrine pathways to modulate embryo development during in vitro culture.</p>","PeriodicalId":136608,"journal":{"name":"Zygote (Cambridge, England)","volume":" ","pages":"297-301"},"PeriodicalIF":1.7,"publicationDate":"2008-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S0967199408004760","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"40423949","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}